Anyone else use hamachi?

So me and a couple friends use hamachi as it makes gaming on certain games a bit easier, and also not horrible for transfering a file or two real quick. Well all of a sudden yesterday the connection through hamachi was being relayed because it couldn't resolve some NAT issue. I thought it was maybe my router (I had JUST gotten a new router) wasn't agreeing with hamachi, so I opened up some ports to work with hamachi and was still having the problem. My friend I was testing with ended up having to open up ports as well. I thought this was really strange because he was using the same router as always and hadnt changed anything. Did hamachi release some sort of update that anyone knows about that was messing with it? We got it resolved by doing that but, it was just really strange.